The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Mark G. Neyland - One of the best experts on this subject based on the ideXlab platform.
-
A synthesis of outcomes from the Warra Silvicultural Systems Trial, Tasmania: safety, timber production, economics, biodiversity, silviculture and social acceptability
Australian Forestry, 2012Co-Authors: Mark G. Neyland, John Hickey, Steve M. ReadAbstract:Summary The Warra Silvicultural Systems Trial was established in southern Tasmania from 1998 to 2007 in tall wet Eucalyptus obliqua forest to compare seven alternatives to the traditional clear-fell, burn and sow (CBS) harvesting method. The alternatives included CBS with understorey islands, patch-fell, strip-fell, dispersed retention, aggregated retention, single-tree/small-group selection and group selection. The effects of the treatments were compared at age three years against six criteria: safety for harvesting crews, rate of timber recovery, economic returns to the forest owner, old-growth biodiversity, regeneration and growth of eucalypts (silviculture), and social acceptability. Combining all criteria, aggregated retention performed best, and is suggested to be the most suitable alternative for routine use in wet eucalypt forests if a management objective is to maintain old-growth structures and biodiversity at the stand (coupe) level. Aggregated retention presented no novel safety issues even th...
-
Early impacts of harvesting and burning disturbances on vegetation communities in the Warra Silvicultural Systems trial, Tasmania, Australia
Australian Journal of Botany, 2011Co-Authors: Mark G. Neyland, S. Jean JarmanAbstract:Impacts on the understorey vegetation of a range of Silvicultural alternatives to clearfelling in lowland Eucalyptus obliqua wet forest were studied over a decade in the Warra Silvicultural Systems trial in southern Tasmania. The treatments were clearfell with understorey islands, patchfell, stripfell, dispersed retention, aggregated retention, and single-tree/small-group selection. High intensity burning, low intensity burning and no burning were variously applied as part of these treatments. Three understorey types were studied, including one wet sclerophyll community and two rainforest communities. Wherever burning occurred across the research trial, the regenerating vegetation was floristically wet sclerophyll with an incipient composition consistent with that of the pre-harvest wet sclerophyll community. Sites previously occupied by rainforest understoreys retained occasional rainforest elements, but the regeneration was overwhelmingly sclerophyll in nature. There were no consistent differences in the floristic composition of the regenerating vegetation, after burning or harvesting disturbance, that could be attributed to the Silvicultural system. However, field observations and the results of a related, subsequent study suggest that, in designing Silvicultural trials similar to the present one, close attention should be paid to the size of quadrats in relation to the level at which disturbance impacts are operating. The response of the vegetation at edges created by the treatments, and in the undisturbed forest beyond, supports the finding that edge effects on the vascular flora extend for less than 10 m into the undisturbed forest.
-
The response of the vegetation to a range of alternatives to clearfelling of tall wet eucalypt forests at the Warra Silvicultural Systems trial, Tasmania, Australia
2010Co-Authors: Mark G. NeylandAbstract:Clearfelling of wet eucalypt forest followed by high intensity burning and aerial sowing, a Silvicultural system used for the last 50 years in Tasmania and designed to mimic the natural dynamic of sporadic regeneration following cataclysmic disturbance, has attracted criticism for not maintaining the structural or floristic diversity that is associated with natural disturbance. To address these concerns, a Silvicultural Systems trial was established at the Warra Long-Term Ecological Research site in southern Tasmania to quantify the effect on these values if variable-retention harvesting Systems are applied to tall wet eucalypt forest. The harvesting treatments were clearfell, burn and sow with understorey islands, a patchfell, stripfell, dispersed retention, aggregated retention, single-tree/small-group selection and group selection. High intensity burning, low intensity burning and no burning were variously applied as part of these treatments. Stocking, density and growth of the eucalypt seedling regeneration, floristic changes and the structural integrity of retained forest areas were monitored for up to ten years after harvesting and regeneration treatments were applied from 1998 to 2007. The nature of the seedbed in each coupe was related to the harvesting and regeneration treatment. Where high intensity burns were applied there was a higher proportion of burnt seedbed available than in coupes where low intensity burns were applied. The highest eucalypt seedling densities and fastest early growth rates occurred on the hottest burnt seedbeds. The lowest seedling densities occurred on unburnt and undisturbed seedbeds and the slowest early growth rates occurred on unburnt and compacted seedbeds. Treatments that created the most burnt seedbed had the highest eucalypt seedling densities and mean seedling growth rates. The floristic response in any given coupe following the harvesting and burning disturbance was related to the pre-harvesting floristics and not to the Silvicultural system. Rainforest species present in the understorey prior to harvesting were also present in the post-harvesting vegetation, albeit at lower levels. Sclerophyll dominated understoreys regenerated with a very similar species composition to that pre-harvesting. Damage to the edges of retained forest areas was minimal, except for the smallest areas, which were prone to windthrow and were often burnt during the regeneration burn. Larger areas persisted intact throughout the harvesting and burning operations and for the first few years after those disturbances. Of the Silvicultural Systems examined in this study, aggregated retention is considered the most promising alternative to clearfelling. High intensity burns as applied to clearfell burn and sow coupes cannot be conducted in aggregated retention coupes as they would probably burn the aggregates. The lower proportion of burnt seedbed resulting will, on average, lead to lower seedling density and growth rates, and may compromise longer term productivity compared to clearfelled and high-intensity-burnt coupes. If aggregated retention is to be successfully applied, as measured by the density and height growth of the regeneration, finding ways of successfully and consistently burning such coupes post-harvesting will be essential.
-
Safety and productivity at the Warra Silvicultural Systems trial.
2009Co-Authors: Mark G. Neyland, J. E. Hickey, L. G. EdwardsAbstract:The Warra Silvicultural Systems trial (Hickey et al. 2001) was established from 1998 to 2007 to develop alternative Silvicultural Systems to clearfell, burn and sow (CBS) that could successfully be applied to the tall wet eucalypt forests of Tasmania, without compromising worker safety. The trial was originally established to develop alternatives for use in areas where habitat, special species or aesthetic values have additional emphasis (Hickey et al. 2001). The Supplementary Tasmanian Regional Forest Agreement between the Commonwealth of Australia and the State of Tasmania (Commonwealth of Australia and State of Tasmania 2005) commi ed Tasmania, amongst other things, to achieving nonclearfelling silviculture in a minimum of 80 per cent of the annual harvest area of couped oldgrowth forest on State forests by 2010. This increased the urgency to extend the experimental alternatives being developed at the Warra Silvicultural Systems trial and extend them to operational coupes throughout the State.
-
An examination of stocking and early growth in the Warra Silvicultural Systems trial confirms the importance of a burnt seedbed for vigorous regeneration in Eucalyptus obliqua forest
Forest Ecology and Management, 2009Co-Authors: Mark G. Neyland, John Hickey, Christopher L. Beadle, Juergen Bauhus, Neil J. Davidson, Leigh EdwardsAbstract:Abstract Clearfelling of wet eucalypt forest followed by high intensity burning and aerial sowing, a Silvicultural system designed to mimic the natural dynamic of sporadic regeneration following cataclysmic disturbance, has attracted criticism for not maintaining the structural diversity that is associated with natural disturbance. A Silvicultural Systems trial was established at the Warra Long-Term Ecological Research site in southern Tasmania to explore alternatives to clearfelling in tall wet eucalypt forest. Stocking, density and growth of the seedling regeneration were monitored for up to 3 years after harvesting and regeneration treatments were applied from 1998 to 2007. The treatments were clearfell with understorey islands, a patchfell, stripfell, dispersed retention, aggregated retention, and single-tree/small-group selection. High intensity burning, low intensity burning and no burning were variously applied as part of these treatments. The nature of the seedbed in each coupe was related to the harvesting and regeneration treatment. Where high intensity burns were applied there was a higher proportion of burnt seedbed available than in coupes where low intensity burns were applied. The highest seedling densities and fastest early seedling growth rates occurred on the hottest burnt seedbeds. The lowest seedling densities occurred on unburnt and undisturbed seedbeds and the slowest early growth rates occurred on unburnt and compacted seedbeds. Treatments that created the most burnt seedbed had the highest seedling densities and the fastest seedling growth. Aggregated retention is considered the most promising alternative to clearfelling. Because high intensity burns as applied to clearfell burn and sow coupes cannot be conducted in aggregated retention coupes as they would probably burn the aggregates, the lower proportion of burnt seedbed will, on average, result in lower seedling density and growth, and may compromise longer term productivity compared to clearfelled and high intensity-burnt coupes. If aggregated retention is to be successfully applied, as measured by the density and height growth of the regeneration, finding ways of successfully and consistently burning such coupes post-harvesting will be essential.
Jacques Bardat - One of the best experts on this subject based on the ideXlab platform.
-
plant diversity in a managed temperate deciduous forest understorey response to two Silvicultural Systems
Journal of Applied Ecology, 2004Co-Authors: Guillaume Decocq, Michael Aubert, Frédéric Dupont, Didier Alard, Robert Saguez, Bruno De Foucault, Annie Wattezfranger, Annick Delelisdusollier, Jacques BardatAbstract:Summary 1 Disturbances and resource availability are key factors affecting plant diversity in managed forests. As disturbance regimes vary among Silvicultural Systems and may simultaneously affect different types of resources, effects on biodiversity can be unpredictable. 2 We compared the effects of two Silvicultural Systems on understorey plant diversity, including species composition, structural attributes and functional organization. One hundred and thirty-five phytosociological releves were sampled from 27 forest stands managed under either a traditional coppice-with-standards (CWS, n = 12) or a ‘close-to-nature’ selective cutting system (SC, n = 15), over similar edaphic conditions. Important environmental factors affecting vegetation were deduced using Ellenberg indicator values. Structural diversity was described using traditional indices of α and β diversity. Guilds were defined within the local pool of species using a set of 14 traits and their relationship with silviculture was assessed using correspondence analysis. 3 Post-logged CWS stands share some compositional and structural characteristics with selectively cut stands, including high species richness and a dominance of early successional species. However the species pool for all coppicing areas was higher than for selectively cut areas, suggesting that the high disturbance frequency occurring in the latter may progressively eliminate the most sensitive species. 4 Functional diversity strongly differs between the two Systems. Although it is conserved through the Silvicultural cycle in the coppice-with-standards system, some guilds were lacking in selectively cut stands. The most negatively impacted guilds were tree and shrub saplings, prostrated ruderals, shade-tolerant perennials and vernal geophytes. The latter two comprise ‘true forest species’ which may also be considered as ‘coppicing-maintained species’. To reach the same values of guild richness (i.e. number of guilds) or redundancy (i.e. proportion of the maximal species richness within each guild), larger areas were required in SC compared with CWS Systems. 5 In the SC system, the high proportion of light reaching the forest floor induced a spectacular spread of blackberries Rubus fruticosus agg., which decreased species richness. It also caused shifts in guild composition: graminoids and ferns grew strongly to the detriment of true forest species. 6 Synthesis and applications. Our results suggest long-term negative effects of selective cutting on both structural and functional plant diversity, compared with coppice-with-standards. Cutting intervals are shorter than recovery times, so that early successional species-dominated communities are maintained. Vernal geophytes and shade-tolerant perennials seem to be limited by the frequency of disturbance rather than by the severity of disturbance. We conclude that, from a biodiversity point of view, this ‘close-to-nature’ system does not cope with the objective of sustainable forest management. The rotations currently in use do not match natural disturbances very closely and are applied to a managed system rather than a natural forest. Retaining remnants of old coppice woods and extending rotations to at least 50 years are recommended where biodiversity conservation is a goal of forest management.
-
Plant diversity in a managed temperate deciduous forest: understorey response to two Silvicultural Systems
Journal of Applied Ecology, 2004Co-Authors: Guillaume Decocq, Michael Aubert, Frédéric Dupont, Didier Alard, Robert Saguez, Annie Wattez Franger, Bruno De Foucault, Annick Delelis Dusolier, Jacques BardatAbstract:1. Disturbances and resource availability are key factors affecting plant diversity in managed forests. As disturbance regimes vary among Silvicultural Systems and may simultaneously affect different types of resources, effects on biodiversity can be unpredictable. 2. We compared the effects of two Silvicultural Systems on understorey plant diversity, including species composition, structural attributes and functional organization. One hundred and thirty-five phytosociological releves were sampled from 27 forest stands managed under either a traditional coppice-with-standards (CWS, n = 12) or a 'close-to-nature' selective cutting system (SC, n = 15), over similar edaphic conditions. Important environmental factors affecting vegetation were deduced using Ellenberg indicator values. Structural diversity was described using traditional indices of alpha and beta diversity. Guilds were defined within the local pool of species using a set of 14 traits and their relationship with silviculture was assessed using correspondence analysis. 3. Post-logged CWS stands share some compositional and structural characteristics with selectively cut stands, including high species richness and a dominance of early successional species. However the species pool for all coppicing areas was higher than for selectively cut areas, suggesting that the high disturbance frequency occurring in the latter may progressively eliminate the most sensitive species. 4. Functional diversity strongly differs between the two Systems. Although it is conserved through the Silvicultural cycle in the coppice-with-standards system, some guilds were lacking in selectively cut stands. The most negatively impacted guilds were tree and shrub saplings, prostrated ruderals, shade-tolerant perennials and vernal geophytes. The latter two comprise 'true forest species' which may also be considered as 'coppicing-maintained species'. To reach the same values of guild richness (i.e. number of guilds) or redundancy (i.e. proportion of the maximal species richness within each guild), larger areas were required in SC compared with CWS Systems. 5. In the SC system, the high proportion of light reaching the forest floor induced a spectacular spread of blackberries Rubus fruticosus agg., which decreased species richness. It also caused shifts in guild composition: graminoids and ferns grew strongly to the detriment of true forest species. 6. Synthesis and applications. Our results suggest long-term negative effects of selective cutting on both structural and functional plant diversity, compared with coppice-with-standards. Cutting intervals are shorter than recovery times, so that early successional species-dominated communities are maintained. Vernal geophytes and shade-tolerant perennials seem to be limited by the frequency of disturbance rather than by the severity of disturbance. We conclude that, from a biodiversity point of view, this 'close-to-nature' system does not cope with the objective of sustainable forest management. The rotations currently in use do not match natural disturbances very closely and are applied to a managed system rather than a natural forest. Retaining remnants of old coppice woods and extending rotations to at least 50 years are recommended where biodiversity conservation is a goal of forest management
Didier Alard - One of the best experts on this subject based on the ideXlab platform.
-
plant diversity in a managed temperate deciduous forest understorey response to two Silvicultural Systems
Journal of Applied Ecology, 2004Co-Authors: Guillaume Decocq, Michael Aubert, Frédéric Dupont, Didier Alard, Robert Saguez, Bruno De Foucault, Annie Wattezfranger, Annick Delelisdusollier, Jacques BardatAbstract:Summary 1 Disturbances and resource availability are key factors affecting plant diversity in managed forests. As disturbance regimes vary among Silvicultural Systems and may simultaneously affect different types of resources, effects on biodiversity can be unpredictable. 2 We compared the effects of two Silvicultural Systems on understorey plant diversity, including species composition, structural attributes and functional organization. One hundred and thirty-five phytosociological releves were sampled from 27 forest stands managed under either a traditional coppice-with-standards (CWS, n = 12) or a ‘close-to-nature’ selective cutting system (SC, n = 15), over similar edaphic conditions. Important environmental factors affecting vegetation were deduced using Ellenberg indicator values. Structural diversity was described using traditional indices of α and β diversity. Guilds were defined within the local pool of species using a set of 14 traits and their relationship with silviculture was assessed using correspondence analysis. 3 Post-logged CWS stands share some compositional and structural characteristics with selectively cut stands, including high species richness and a dominance of early successional species. However the species pool for all coppicing areas was higher than for selectively cut areas, suggesting that the high disturbance frequency occurring in the latter may progressively eliminate the most sensitive species. 4 Functional diversity strongly differs between the two Systems. Although it is conserved through the Silvicultural cycle in the coppice-with-standards system, some guilds were lacking in selectively cut stands. The most negatively impacted guilds were tree and shrub saplings, prostrated ruderals, shade-tolerant perennials and vernal geophytes. The latter two comprise ‘true forest species’ which may also be considered as ‘coppicing-maintained species’. To reach the same values of guild richness (i.e. number of guilds) or redundancy (i.e. proportion of the maximal species richness within each guild), larger areas were required in SC compared with CWS Systems. 5 In the SC system, the high proportion of light reaching the forest floor induced a spectacular spread of blackberries Rubus fruticosus agg., which decreased species richness. It also caused shifts in guild composition: graminoids and ferns grew strongly to the detriment of true forest species. 6 Synthesis and applications. Our results suggest long-term negative effects of selective cutting on both structural and functional plant diversity, compared with coppice-with-standards. Cutting intervals are shorter than recovery times, so that early successional species-dominated communities are maintained. Vernal geophytes and shade-tolerant perennials seem to be limited by the frequency of disturbance rather than by the severity of disturbance. We conclude that, from a biodiversity point of view, this ‘close-to-nature’ system does not cope with the objective of sustainable forest management. The rotations currently in use do not match natural disturbances very closely and are applied to a managed system rather than a natural forest. Retaining remnants of old coppice woods and extending rotations to at least 50 years are recommended where biodiversity conservation is a goal of forest management.
-
Plant diversity in a managed temperate deciduous forest: understorey response to two Silvicultural Systems
Journal of Applied Ecology, 2004Co-Authors: Guillaume Decocq, Michael Aubert, Frédéric Dupont, Didier Alard, Robert Saguez, Annie Wattez Franger, Bruno De Foucault, Annick Delelis Dusolier, Jacques BardatAbstract:1. Disturbances and resource availability are key factors affecting plant diversity in managed forests. As disturbance regimes vary among Silvicultural Systems and may simultaneously affect different types of resources, effects on biodiversity can be unpredictable. 2. We compared the effects of two Silvicultural Systems on understorey plant diversity, including species composition, structural attributes and functional organization. One hundred and thirty-five phytosociological releves were sampled from 27 forest stands managed under either a traditional coppice-with-standards (CWS, n = 12) or a 'close-to-nature' selective cutting system (SC, n = 15), over similar edaphic conditions. Important environmental factors affecting vegetation were deduced using Ellenberg indicator values. Structural diversity was described using traditional indices of alpha and beta diversity. Guilds were defined within the local pool of species using a set of 14 traits and their relationship with silviculture was assessed using correspondence analysis. 3. Post-logged CWS stands share some compositional and structural characteristics with selectively cut stands, including high species richness and a dominance of early successional species. However the species pool for all coppicing areas was higher than for selectively cut areas, suggesting that the high disturbance frequency occurring in the latter may progressively eliminate the most sensitive species. 4. Functional diversity strongly differs between the two Systems. Although it is conserved through the Silvicultural cycle in the coppice-with-standards system, some guilds were lacking in selectively cut stands. The most negatively impacted guilds were tree and shrub saplings, prostrated ruderals, shade-tolerant perennials and vernal geophytes. The latter two comprise 'true forest species' which may also be considered as 'coppicing-maintained species'. To reach the same values of guild richness (i.e. number of guilds) or redundancy (i.e. proportion of the maximal species richness within each guild), larger areas were required in SC compared with CWS Systems. 5. In the SC system, the high proportion of light reaching the forest floor induced a spectacular spread of blackberries Rubus fruticosus agg., which decreased species richness. It also caused shifts in guild composition: graminoids and ferns grew strongly to the detriment of true forest species. 6. Synthesis and applications. Our results suggest long-term negative effects of selective cutting on both structural and functional plant diversity, compared with coppice-with-standards. Cutting intervals are shorter than recovery times, so that early successional species-dominated communities are maintained. Vernal geophytes and shade-tolerant perennials seem to be limited by the frequency of disturbance rather than by the severity of disturbance. We conclude that, from a biodiversity point of view, this 'close-to-nature' system does not cope with the objective of sustainable forest management. The rotations currently in use do not match natural disturbances very closely and are applied to a managed system rather than a natural forest. Retaining remnants of old coppice woods and extending rotations to at least 50 years are recommended where biodiversity conservation is a goal of forest management
Guillaume Decocq - One of the best experts on this subject based on the ideXlab platform.
-
plant diversity in a managed temperate deciduous forest understorey response to two Silvicultural Systems
Journal of Applied Ecology, 2004Co-Authors: Guillaume Decocq, Michael Aubert, Frédéric Dupont, Didier Alard, Robert Saguez, Bruno De Foucault, Annie Wattezfranger, Annick Delelisdusollier, Jacques BardatAbstract:Summary 1 Disturbances and resource availability are key factors affecting plant diversity in managed forests. As disturbance regimes vary among Silvicultural Systems and may simultaneously affect different types of resources, effects on biodiversity can be unpredictable. 2 We compared the effects of two Silvicultural Systems on understorey plant diversity, including species composition, structural attributes and functional organization. One hundred and thirty-five phytosociological releves were sampled from 27 forest stands managed under either a traditional coppice-with-standards (CWS, n = 12) or a ‘close-to-nature’ selective cutting system (SC, n = 15), over similar edaphic conditions. Important environmental factors affecting vegetation were deduced using Ellenberg indicator values. Structural diversity was described using traditional indices of α and β diversity. Guilds were defined within the local pool of species using a set of 14 traits and their relationship with silviculture was assessed using correspondence analysis. 3 Post-logged CWS stands share some compositional and structural characteristics with selectively cut stands, including high species richness and a dominance of early successional species. However the species pool for all coppicing areas was higher than for selectively cut areas, suggesting that the high disturbance frequency occurring in the latter may progressively eliminate the most sensitive species. 4 Functional diversity strongly differs between the two Systems. Although it is conserved through the Silvicultural cycle in the coppice-with-standards system, some guilds were lacking in selectively cut stands. The most negatively impacted guilds were tree and shrub saplings, prostrated ruderals, shade-tolerant perennials and vernal geophytes. The latter two comprise ‘true forest species’ which may also be considered as ‘coppicing-maintained species’. To reach the same values of guild richness (i.e. number of guilds) or redundancy (i.e. proportion of the maximal species richness within each guild), larger areas were required in SC compared with CWS Systems. 5 In the SC system, the high proportion of light reaching the forest floor induced a spectacular spread of blackberries Rubus fruticosus agg., which decreased species richness. It also caused shifts in guild composition: graminoids and ferns grew strongly to the detriment of true forest species. 6 Synthesis and applications. Our results suggest long-term negative effects of selective cutting on both structural and functional plant diversity, compared with coppice-with-standards. Cutting intervals are shorter than recovery times, so that early successional species-dominated communities are maintained. Vernal geophytes and shade-tolerant perennials seem to be limited by the frequency of disturbance rather than by the severity of disturbance. We conclude that, from a biodiversity point of view, this ‘close-to-nature’ system does not cope with the objective of sustainable forest management. The rotations currently in use do not match natural disturbances very closely and are applied to a managed system rather than a natural forest. Retaining remnants of old coppice woods and extending rotations to at least 50 years are recommended where biodiversity conservation is a goal of forest management.
-
Plant diversity in a managed temperate deciduous forest: understorey response to two Silvicultural Systems
Journal of Applied Ecology, 2004Co-Authors: Guillaume Decocq, Michael Aubert, Frédéric Dupont, Didier Alard, Robert Saguez, Annie Wattez Franger, Bruno De Foucault, Annick Delelis Dusolier, Jacques BardatAbstract:1. Disturbances and resource availability are key factors affecting plant diversity in managed forests. As disturbance regimes vary among Silvicultural Systems and may simultaneously affect different types of resources, effects on biodiversity can be unpredictable. 2. We compared the effects of two Silvicultural Systems on understorey plant diversity, including species composition, structural attributes and functional organization. One hundred and thirty-five phytosociological releves were sampled from 27 forest stands managed under either a traditional coppice-with-standards (CWS, n = 12) or a 'close-to-nature' selective cutting system (SC, n = 15), over similar edaphic conditions. Important environmental factors affecting vegetation were deduced using Ellenberg indicator values. Structural diversity was described using traditional indices of alpha and beta diversity. Guilds were defined within the local pool of species using a set of 14 traits and their relationship with silviculture was assessed using correspondence analysis. 3. Post-logged CWS stands share some compositional and structural characteristics with selectively cut stands, including high species richness and a dominance of early successional species. However the species pool for all coppicing areas was higher than for selectively cut areas, suggesting that the high disturbance frequency occurring in the latter may progressively eliminate the most sensitive species. 4. Functional diversity strongly differs between the two Systems. Although it is conserved through the Silvicultural cycle in the coppice-with-standards system, some guilds were lacking in selectively cut stands. The most negatively impacted guilds were tree and shrub saplings, prostrated ruderals, shade-tolerant perennials and vernal geophytes. The latter two comprise 'true forest species' which may also be considered as 'coppicing-maintained species'. To reach the same values of guild richness (i.e. number of guilds) or redundancy (i.e. proportion of the maximal species richness within each guild), larger areas were required in SC compared with CWS Systems. 5. In the SC system, the high proportion of light reaching the forest floor induced a spectacular spread of blackberries Rubus fruticosus agg., which decreased species richness. It also caused shifts in guild composition: graminoids and ferns grew strongly to the detriment of true forest species. 6. Synthesis and applications. Our results suggest long-term negative effects of selective cutting on both structural and functional plant diversity, compared with coppice-with-standards. Cutting intervals are shorter than recovery times, so that early successional species-dominated communities are maintained. Vernal geophytes and shade-tolerant perennials seem to be limited by the frequency of disturbance rather than by the severity of disturbance. We conclude that, from a biodiversity point of view, this 'close-to-nature' system does not cope with the objective of sustainable forest management. The rotations currently in use do not match natural disturbances very closely and are applied to a managed system rather than a natural forest. Retaining remnants of old coppice woods and extending rotations to at least 50 years are recommended where biodiversity conservation is a goal of forest management
John Hickey - One of the best experts on this subject based on the ideXlab platform.
-
A synthesis of outcomes from the Warra Silvicultural Systems Trial, Tasmania: safety, timber production, economics, biodiversity, silviculture and social acceptability
Australian Forestry, 2012Co-Authors: Mark G. Neyland, John Hickey, Steve M. ReadAbstract:Summary The Warra Silvicultural Systems Trial was established in southern Tasmania from 1998 to 2007 in tall wet Eucalyptus obliqua forest to compare seven alternatives to the traditional clear-fell, burn and sow (CBS) harvesting method. The alternatives included CBS with understorey islands, patch-fell, strip-fell, dispersed retention, aggregated retention, single-tree/small-group selection and group selection. The effects of the treatments were compared at age three years against six criteria: safety for harvesting crews, rate of timber recovery, economic returns to the forest owner, old-growth biodiversity, regeneration and growth of eucalypts (silviculture), and social acceptability. Combining all criteria, aggregated retention performed best, and is suggested to be the most suitable alternative for routine use in wet eucalypt forests if a management objective is to maintain old-growth structures and biodiversity at the stand (coupe) level. Aggregated retention presented no novel safety issues even th...
-
An examination of stocking and early growth in the Warra Silvicultural Systems trial confirms the importance of a burnt seedbed for vigorous regeneration in Eucalyptus obliqua forest
Forest Ecology and Management, 2009Co-Authors: Mark G. Neyland, John Hickey, Christopher L. Beadle, Juergen Bauhus, Neil J. Davidson, Leigh EdwardsAbstract:Abstract Clearfelling of wet eucalypt forest followed by high intensity burning and aerial sowing, a Silvicultural system designed to mimic the natural dynamic of sporadic regeneration following cataclysmic disturbance, has attracted criticism for not maintaining the structural diversity that is associated with natural disturbance. A Silvicultural Systems trial was established at the Warra Long-Term Ecological Research site in southern Tasmania to explore alternatives to clearfelling in tall wet eucalypt forest. Stocking, density and growth of the seedling regeneration were monitored for up to 3 years after harvesting and regeneration treatments were applied from 1998 to 2007. The treatments were clearfell with understorey islands, a patchfell, stripfell, dispersed retention, aggregated retention, and single-tree/small-group selection. High intensity burning, low intensity burning and no burning were variously applied as part of these treatments. The nature of the seedbed in each coupe was related to the harvesting and regeneration treatment. Where high intensity burns were applied there was a higher proportion of burnt seedbed available than in coupes where low intensity burns were applied. The highest seedling densities and fastest early seedling growth rates occurred on the hottest burnt seedbeds. The lowest seedling densities occurred on unburnt and undisturbed seedbeds and the slowest early growth rates occurred on unburnt and compacted seedbeds. Treatments that created the most burnt seedbed had the highest seedling densities and the fastest seedling growth. Aggregated retention is considered the most promising alternative to clearfelling. Because high intensity burns as applied to clearfell burn and sow coupes cannot be conducted in aggregated retention coupes as they would probably burn the aggregates, the lower proportion of burnt seedbed will, on average, result in lower seedling density and growth, and may compromise longer term productivity compared to clearfelled and high intensity-burnt coupes. If aggregated retention is to be successfully applied, as measured by the density and height growth of the regeneration, finding ways of successfully and consistently burning such coupes post-harvesting will be essential.
-
Rationale and design for the Warra Silvicultural Systems trial in wet Eucalyptus obliqua forests in Tasmania
2001Co-Authors: John Hickey, Mark G. Neyland, Od BassettAbstract:Clemfell, burn and sow (CBS) is the prescribed Silvicultural technique for wood production from lowland wet eucalypt forests. Its widespread adoption raises concerns, particularly due to initial aesthetics, a reduction in late successional species and structures, and a decline in the special species timbers resource when rotations of about 90 years are used. Cases for and against the CBS technique are presented. The Warra Silvicultural Systems trial is being established in the period 1998-2002 to compare CBS with five alternative treatments that were selected after a review of Silvicultural Systems applied in 'Wet forests elsewhere. The alternatives include CBS with understorey islands, stripfell/patchfell, 10% dispersed retention, 30% aggregated retention and single tree/small group selection. Prescriptions for the six treatments and indicators for monitoring their initial pe1formance are described, along with expectations and limitations of the Warra trial.
